The officers -- about 30 in number -- are defectors mostly from the town of Lviv in western Ukraine, where most look toward Europe in a divided nation that has long split allegiance between Europe and Russia.

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Their commander, Vassily Krikowsky, decided to lead them to Kiev after seeing the images of bloodied protesters, some killed -- opposition officials say -- at the hands of security forces.

"We want to make a statement that we cannot tolerate this any longer," he said. "We are from western Ukraine, and we want to show everyone that the police is with the people."

The question of whether some police officers were defecting amid the violence took center stage on Thursday, when the government said protesters had taken several dozen police officers hostage.

However, other officers appeared on Ukrainian television saying they had defected after receiving orders to use force on protesters.

It's unclear what might happen to the men. An agreement signed Friday by government and opposition leaders requires protesters and security forces alike to withdraw from the streets and turn in illegal weapons.

It appears to protect protesters from prosecution for illegal weapons possession during the protest. But it doesn't address the case of police officers who walked away from their jobs to join and help defend protesters against their comrades.

Although things are peaceful today, the men are well aware that they might have to confront their colleagues on the other side of the barricades if the situation escalates again.

"Some police officers have committed crimes," Krikowsky said. "By shooting at unarmed people and medical volunteers. Those are crimes."